The present invention relates generally to data processing systems and, more particularly, to network reconfiguration.
xe2x80x9cconfiguring a networkxe2x80x9d refers to changing the topology of the network (e.g., adding a node or removing a node). A xe2x80x9cnetwork topologyxe2x80x9d refers to the structure that provides the communications interconnection among nodes of a network. As used herein, the term xe2x80x9cnodexe2x80x9d refers to any device capable of communicating, such as a computer, router, switch, network processor, or symmetric multiprocessor. Thus, the topology of a network refers to the network""s particular configuration of links and nodes.
In conventional static-routing networks, reconfiguring a network requires four steps as shown in FIG. 1. A static-routing network uses statically-defined routing tables to perform routing. The routing is considered to be static because if the network is reconfigured, all of the routing tables need to be manually updated to account for the reconfiguration. For example, if the reconfiguration involves removing a node, the routing tables need to be updated to avoid routing through this node. And if the reconfiguration involves adding a node, the routing tables need to be updated to route to the new node.
When reconfiguring a static-routing network, the network administrator first terminates all processes communicating via the network (step 102). Next, the system administrator reconfigures the network by adding or removing a node and by performing the appropriate recabling (step 104). Then, the network administrator updates the routing tables in the network to account for the reconfiguration (e.g., avoid the removed node) (step 106) and, finally, restarts the processes that were terminated (step 108). By reconfiguring networks in this manner, the networks are rendered nonoperational for a significant amount of time, such as a few hours. It is thus desirable to improve how networks are reconfigured.
In accordance with methods and systems consistent with the present invention, an improved technique for reconfiguring networks is provided. By using this technique, a network administrator can reconfigure their network while it remains operational. As a result, users can continue to utilize the network during reconfiguration. Additionally, in accordance with methods and systems consistent with the present invention, a number of network topologies are provided that are designed to facilitate reconfiguration. When using one of these topologies, the network can be reconfigured with a minimal amount of recabling, thus reducing the amount of time required for reconfiguration.
In accordance with methods consistent with the present invention, a method is provided in a distributed system containing a network with nodes, where each of the nodes has ports. This method configures the network to maximize port usage, renders the network operational such that the nodes are capable of communicating via the network using static routing, and reconfigures the network while the network remains operational.